Police departments in Chicago and the suburbs have embraced the Taser, a device marketed as a tool to reduce shootings by officers.

The weapons' manufacturer contends that if officers can use electric shocks to prevent dangerous situations from escalating, police might shoot their guns less.

But that hasn't happened in Chicago.

In 2010, the city armed hundreds more officers with the weapon, fueling a 329 percent jump in Taser use, from 195incidents in 2009to 836in 2011. Yet shootings by police didn't drop significantly during that period, according to figures from the city's Independent Police Review Authority.

The numbers raise questions about how often police use the weapons to defuse confrontations that might otherwise escalate to use of deadly force. Civil lawyers and department critics have alleged that, rather than deploying Tasers to subdue dangerous criminals, officers have sometimes drawn them on mildly obstinate suspects.

Top-ranking police said they believe officers are using the weapons with restraint,and they gave several explanations as to how skyrocketing Taser use could fail to cut the shooting numbers. Officials initially cited an uptick in attacks on officers, though department statistics indicate that instances of battery of officers actually have dropped.

Department rules grant officers wide latitude in deploying the weapons, authorizing them against both violent assailants and people who run away or make an "evasive movement of the arm." Though Tasers can be valuable tools, experts said, officers generally should not deliver debilitating shocks to people who are fleeing or lightly resisting being handcuffed.

Experts said a police chief should expect an increase in Taser use to cut shootings, if other circumstances remain similar from one year to the next. If shootings are not reduced, a department should question whether something else significantchanged or if officers are using force too readily.

"The big investment in Taser is meant to preserve lives," said Roy Bedard, a Florida-based consultant on policing and use of force. "If you're Tasing more people and you're still shooting more people, well, something's wrong."

But Chicago police said conditions on the street never remain stable and cited department statistics indicating that officers are using other kinds of force, including pepper spray and "impact weapons" such as batons, less often. However, the department did not providedetailed data to explain more completely how officers have used other kinds of force since the introduction of the Taser.

Officers need broad discretion to make their own decisions, and they are taught to consider all circumstances before deploying a Taser, said Chicago policeSgt. Michael Partipilo, who is in charge of training police on the devices.

"(Officers) ask me, 'What if this happens?'" he said. "I answer the same, exact way every time: 'I don't know, I can't answer that. You'll have to answer that when you're there.'"

Civil lawyers allege that officers made bad choices in two recent cases, one in which a man claims police shocked him repeatedly and another in which police said an officer jolted a pregnant woman who tore up a parking ticket, threw it at an officer and prepared to drive off.

Officers pulled Josue Tapia from his vehicle after mistaking him for a wanted man in May 2010 and shocked him 11 times, said his lawyer, Blake Horwitz. Tapia was charged with resisting arrest and aggravated battery on a police officer, but he was acquitted in November, according to court records.

"I'm not able to go in public places or even go to work because I feel like something bad is going to happen to me for no good reason," Tapia said.

CPD embraces the Taser

Chicago is a microcosm of Taser International's success at arming police worldwide. The Arizona-based company went from equipping about 500 departments in 2000 to about 16,900 agencies as ofthis spring, said company spokesman Steve Tuttle.

The weapons, pioneered by a University of Chicago-educated aerospace scientist, fire sharp probes linked to wires that rob their targets of muscular control. Tasers also have a pain compliance mode in which the user gives shocks by pressing the weapon against the target.

Observers disagree on the weapon's safety. Human rights group Amnesty International has counted about 500 deaths following use of an electroshock device in the U.S. since 1990, though many were attributed to other causes.

Taser International leaders point to a 2011 study by the U.S. Department of Justice that found "no clear medical evidence that shows a high risk of serious injury or death from the direct effects" of the weapons. That study, however, noted that more research is needed.

In 2010 the city used federal grant money to expand its arsenal to more than 600 — enough to arm one officer in every beat car and outfit tactical, rapid response and other units.

And the department's enthusiasm hasn't waned. The city is replacing its Tasers with the X2, a new version armed with an extra set of electroshock probes for backup firepower if the first set doesn't work. Department officials said they could not discuss the price because the contract was in the works, but Tuttle said departments can trade up to the package that includes the new device for about $1,300 each.

At that price, replacing 600 Tasers would cost $780,000.

Tasers also are popular with suburban departments. Citing data through last fall, the Tribune in January revealed that a handful of suburban departments were on pace to use them roughly twice as often in 2011 as they did in 2008.

Taser use jumps

Few would advise an officer to draw a Taser in a situation that calls for deadly force, but one of the manufacturer's key sales pitches is that the weapons can be used to prevent bad situations from growing worse. On its website, Taser International names agencies that reported a drop in shootings after the device's adoption.

Chicago police have echoed the argument that officers use Tasers to prevent situations from escalating to the use of deadly force.

"If you can bring another option before you get to that level where deadly force might be necessary, I think it's a good thing," said then-Superintendent Jody Weis in March 2010, after the department began expanding the Taser program.

But records obtained by the Tribune of about 2,200 police uses of guns and Tasers from 2009 through 2011 show police have not significantly cut back on deadly force as they ramped up Taser use.

Officers took quickly to the Tasers after the expansion, using them about 840 times in 2011, up from 195 in 2009, according to data provided by the city-run Independent Police Review Authority, a department oversight agency.

In 2009, the year before the Taser expansion, officers recorded 114 shooting incidents, 56 in which a person was hit, according to the data. The shooting numbers dipped in 2010 but bounced back in 2011, as police reported 109 shooting incidents, 58 of which involved a hit.

The data on shootings and Taser shocks provided by the review authority differ slightly from figures the agency posted online. Those discrepancies result from the timing and manner of the agency's notification of the use-of-force incidents, said Ilana Rosenzweig, the review authority's chief administrator.

The records show that Tasers, like the other modes of force, have been most frequently used against minorities, closely mirroring figures indicating blacks and Hispanics accounted for 90 percent of 2010 arrests. About 92 percent of the Taser uses in which race was reported involved a black or Hispanic subject from 2009 through 2011, according to the review authority.

Department spokeswoman Lt. Maureen Biggane said officers "are expected to enforce the law impartially and professionally."

Police shootings and shocks also have been most common in impoverished swaths of the West and South sides, where arrest rates and violent crime are generally high.

The department's far-and-away leader in shootings and Taser shocks was the 11th District, which takes in the East and West Garfield Park neighborhoods as well as part of the Humboldt Park community area.

As it did citywide , Taser use took off steeply in the 11th after more police were armed in 2010. After logging 23 incidents in 2009, officers used Tasers at least 90 times in each of the following two years.

Yet shootings didn't budge, with officers logging nine incidents in 2009, eight in 2010 and 11 the next year.

Police officials argued that the explosion in Taser use shouldn't necessarily dent the shooting numbers.

"Even if the numbers remain constant, every situation is unique," Biggane said in an email.

Fraternal Order of Police spokesman Pat Camden said the numbers alone don't account for shootings that might have been avoided because of the use of a Taser.

Police officials also said that Taser use might have jumped without lowering the shooting numbers because violence against officers is up.

Yet department figures show officers reported 3,299 batteries against them in 2009 and 3,105 in 2011. Questioned about that, Biggane pointed to nationwide numbers indicating a jump in the number of officers who were victims of homicide.

Biggane also said Tasers might have started replacing other weapons, including pepper spray. She cited department statistics that she said show pepper spray incidents dropped from 449 in 2008 to 297 in 2011 and that the use of "impact weapons" such as batons dipped from 178 to 153 during that period. "Emergency handcuffing/takedown" incidents dropped from 4,609 in 2008 to 4,212 in 2011, she said.

But the department did not respond to a request for data that might reveal trends in the use of other kinds of force.

Use-of-force statistics are swayed by factors such as crime rates and the aggressiveness of patrols, but a large department should be able to use Tasers to prevent some shootings, said Geoffrey Alpert, a University of South Carolina criminal justice professor who co-authored the 2011 federal study on the weapons.

"That's how Taser sold themselves to Americans," Alpert said.

In some cities, said Tuttle, the Taser International spokesman, the weapons have been used to short-circuit situations that might have escalated. Just as vitally, he argued, the weapons are often safer for police and arrestees than lower-tech means of controlling suspects, such as tackling them.

Controversial uses persist

Each Chicago police officer receives eight hours of training for initial certification, and Partipilo, the training sergeant, encourages every officer to take a Taser shock.

Partipilo said he teaches officers to assess each situation, from the strength of the officer to the potential dangerousness of the suspect escaping, to decide independently what level of force to deploy. They should keep in mind, for example, that the most serious force might not be appropriate against youths, he said.

The figures provided by the review authority show that Tasers have been used repeatedly against the young and the old. Forty-nine boys and girls under age 16, including children as young as 8, were shocked from 2009 through 2011. Chicago police used Tasers on 11 people 60 or older, the oldest being an 82-year-old man who was listed as having an irregular heartbeat after the encounter.

When asked whether the department's use of Tasers on the young and old indicated excessive use, Biggane said it did not.

"Every use of force incident depends on the totality of the circumstances," she said.

Partipilo said he thinks police have generally made good choices with the Taser.

"We haven't really had big, noteworthy abuses," he said.

But in the two highest-profile recent Taser uses, officers are alleged to have used the weapons in ways experts see as questionable.

In the case of 30-year-old Tiffany Rent, who said she was eight months pregnant when she was shocked June 5 after allegedly tearing up a parking ticket on the South Side, police said an officer deployed the Taser as she tried to shift her SUV into gear.

It is unclear how close Rent allegedly got to putting the vehicle in motion. However, the Police Executive Research Forum, a national police research organization, advised in its 2011 Taser guidelines against shocking people in control of moving vehicles. Before the confrontation with Rent, Partipilo said of using a Taser on a person driving a car, "It's insanity. We can't do it."

Jolting pregnant women also should be avoided, according to the Police Executive Research Forum. Rent is suing the department.

As to Tapia, whose lawyer said he has evidence that indicates officers activated their Tasers 11 times, the 2011 Justice Department study found that many deaths following electroshock use involved multiple jolts, and the study's authors urged caution because "the associated risks are unknown."

If a few tries with a Taser don't subdue a suspect, Alpert advised, "move on to something else."

Police and the city's Law Department declined to comment on the cases.

While Taser use has risen dramatically, there has not been a proportionate jump in complaints to the review authority, Rosenzweig said.

Rosenzweig's agency, however, scaled back investigations of Taser incidents just as use by officers exploded. Until 2010, each incident spurred an extensive investigation that could involve interviewing victims or witnesses.

Deeper investigations are still triggered by allegations of misconduct, when minors or the elderly are involved or when a person is badly hurt or killed. But since 2010, many incidents have received a less thorough review that involves inspecting police documentation of the Taser use. The agency does not have resources to more thoroughly audit every Taser use, Rosenzweig said.

Although the agency provided data to the Tribune on Taser shocks and shootings, the review authority cited exemptions to the state's open records law in declining to release records detailing investigations into individual Taser incidents. Those records might further explain the situations that spurred officers to draw their Tasers.

Those split-second decisions can carry lasting consequences, said Craig Futterman, a University of Chicago law professor who studies policing and believes Chicago police have used Tasers too readily.

In a city stricken by violence, police need cooperation, particularly in troubled neighborhoods, he said. Any unwarranted use of force works against that goal, Futterman said.